Deliberate mistake: Morse code takes a lot longer to type out than the captain of the Dallas seems to need. Likely "compressed" because otherwise the process would be quite dull, but still.
Deliberate mistake: The torpedo hitting the water dropped by the Russian Bear Foxtrot, and the one dropped by the Americans are the same piece of footage.
Answer: The trench is too deep to recover anything from the bottom of the trench. They were going to fake destroying the Red October, so they need some way to explain the lack of evidence of its destruction (because the remains were on the bottom of this deep trench).
Bruce Minnick